by Jeff FoustMonday, April 30, 2018

When NASA’s New Horizons spacecraft flew past Pluto and its moons in July 2015, returning remarkable images and other data of these worlds, it was a culmination of an effort much longer than most people recognized. They knew that the spacecraft had been traveling from Earth for nine and a half years to reach Pluto, and probably understood that the spacecraft had been in development for several years before its January 2006 launch. But convincing NASA to fly a mission to Pluto in the first place, and then keeping the agency sold on the mission, was an effort as long and as difficult as the scientific and technical challenges of New Horizons.

A 1989 dinner was “the turning point where it all went from gee-whiz hallway conversations to a larger, more systemic plan of attack to try to accomplish something” regarding a Pluto mission.

Alan Stern, the principal investigator of New Horizons and the driving force behind flying a Pluto mission, tells that story well in Chasing New Horizons, co-authored by fellow planetary scientist David Grinspoon. It’s a fascinating story of the advances, setbacks, and eventual triumph of a decades-long effort to complete the initial reconnaissance of the solar system.

Stern’s interest in a mission to Pluto dates back to the 1980s. Working on his doctorate at the University of Colorado—a return to academia after several years in industry—he wondered if he had missed out on the golden age of planetary exploration, now that Voyager 2 was performing its flybys of Uranus and Neptune. “I think I’m different from most people in our field in the extent to which I’m really inspired by exploration itself, independent of the science,” he said.

Scientists, though, didn’t share that view, arguing that any mission to Pluto needed to be justified by the science it could produce. Stern started to build up that “critical mass of support” among scientists, which became known as the Pluto Underground. The origin of what would become New Horizons, Stern and Grinspoon argue, was a dinner at an “unremarkable” Italian restaurant in Baltimore in May 1989, during a meeting of the American Geophysical Union. That conference featured a session on Pluto science, and Stern had also recently met with a NASA official who appeared willing to support a study of a Pluto mission. That dinner, recalled another attendee, was “the turning point where it all went from gee-whiz hallway conversations to a larger, more systemic plan of attack to try to accomplish something.”

They accomplished a lot initially, including a mission concept called “Pluto 350,” for its 350-kilogram mass, that could cost far less than a flagship-class mission like Voyager. The “Plutophiles,” though, struggled to maintain that momentum in the 1990s. There were competing concepts, both for far larger and more expensive missions, and for even smaller missions like JPL’s Pluto Fast Flyby. (As a Caltech undergrad in 1992, I was tangentially involved in some of the Pluto Fast Flyby work, including helping build a full-scale model of the spacecraft that went on display at the World Space Congress in Washington that year.)

New NASA administrator Dan Goldin, with his “faster, better, cheaper” mantra, also shook things up, making demands on the size and cost of the spacecraft that others deemed unreasonable. Wes Huntress, who led NASA’s planetary science division at the time, recalled meeting Goldin for the first time and being asked by the new administrator to “send a mission to Pluto to get a sample from the surface and return it to Earth in less than a decade and do it for less than $100 million.”

The effort to send a mission to Pluto suffered a number of near-death experiences in the 1990s and early 2000s, including the cancellation of a competition to select instruments for one mission concept, Pluto Kuiper Express. Stern and Grinspoon discuss those challenges, including a decision Stern faced in early 2001, as NASA planned a competition for a lower-cost Pluto mission: should he work with JPL, with its long heritage of planetary missions, or the Applied Physics Laboratory (APL), which offered a stronger commitment to support the mission. He went with APL, and its New Horizons proposal was ultimately selected by NASA in late 2001.

The book recalls the joy of the successful flyby. Stern says that “it really felt like we’d all had a peak experience in our lives. We’d reached and then summited our own metaphorical mountain, Pluto.”

Stern’s battle to get NASA to do a Pluto mission, and then fund and support it once selected, wasn’t a solo battle. He had support from scientists and space advocates and, politically, Sen. Barbara Mikulski of Maryland, who blocked efforts by the administration to cancel the mission just months after its selection. There were also lesser-known heroes, including a Marshall Space Flight Center manager assigned by NASA to be its project manager for the mission. That manager, Todd May, identified a number of problems with the mission and helped convince NASA to more fully support the mission to overcome those issues. May, now the director of Marshall, “became a hero of New Horizons and a savior of the exploration of Pluto,” Stern and Grinspoon write.

After all those efforts to get a Pluto mission launched, the actual flight of the mission to Pluto might seem a little anticlimactic, given the success it ultimately enjoyed in its flyby. But the book does go into detail about the years of work that went into the planning for the flyby and the issues along the way, including the computer problem just a week and a half before closest approach that put the flyby into jeopardy. It also, of course, recalls the joy of the successful flyby. Stern says that “it really felt like we’d all had a peak experience in our lives. We’d reached and then summited our own metaphorical mountain, Pluto.”

Chasing New Horizons offers a fascinating look at what it took to make New Horizons a reality. There is some discussion of the science of the mission, but the focus is on the development of the mission itself, and the reward that came from decades of work and a realization of a vision to explore a distant world.

The New Horizons mission continues: the spacecraft is set to fly by a Kuiper Belt object, 2014 MU69, now known as “Ultima Thule,” on New Year’s Day 2019, and the spacecraft should be able to operate well into the 2030s as it coasts into interstellar space (see “Next Christmas in the Kuiper Belt”, The Space Review, January 2, 2018). That extended coda is fitting for a mission whose development was as challenging as New Horizons.

Jeff Foust (jeff@thespacereview.com) is the editor and publisher of The Space Review, and a senior staff writer with SpaceNews. He also operates the Spacetoday.net web site. Views and opinions expressed in this article are those of the author alone.